1. Field of the Invention
The present invention relates to a practical and commercially feasible method, device and system for reducing the draft of large vessels so as to eliminate unnecessary dredging and to facilitate full utilization of the ship's cargo capacity. The present invention sophisticates and dramatically improves the state of the art by such means as continuously monitoring the ship's draft, hog, sag, trim, and list conditions and providing means to continuously inflate and deflate the lift cells according to these conditions.
2. Description of the Prior Art
U.S. Pat. No. 3,198,157 issued to Amilcas Con Livas entitled "Draft Reducing Device for Vessels" teaches a method and apparatus for reducing the draft of ships when they are leaving or entering a harbor having insufficient water depth for accommodating such sea-going vessels. The draft reducing means of this invention comprises a first bracket means which is adapted to be secured to the sides of the ship and having a portion extended downwardly from an outboard position thereof, a floatable body and a second bracket means secured to the sides of the floatable body and having an extension depending upwardly from an outboard portion thereof; the upper profile of the second bracket means being interlockable with the lower profile of the first bracket. The floatable body of this invention is described as a hollow buoyant body and according to the invention, can be old tankers. The hollow buoyant body contains sea water ballast that can be pumped out to reduce the draft of the vessel.
U.S. Pat. No. 3,171,377 issued to I. A. Livas, entitled "Draft Reducing Device for Vessels" relates to a method and apparatus for reducing the draft of vessels when they are leaving or entering a harbor having insufficient water depth for accommodating such sea-going vessels. The draft reducing adaptor comprises a flexible, inflatable container adapted for receiving air under pressure, attachment means securable to said container and adapted to be fastened to the side of a vessel so that at least a portion of the container is below the water line, and means automaticaly folding the flexible container flatly against the side of the vessel when air is removed from the inflated container. The container is connected to the ship's side at least along one longitudinal line element of the container below the water line and inflating the container before entering the harbor. An attachment device is welded to the ship's side to facilitate coupling the container to the ship. Additionally, a cover member is provided to protect the deflated flexible container from injury both during a sea voyage and while the ship is approaching or is tied up at its dock after negotiating the harbor waters.
U.S. Pat. No. 2,892,434 issued to James Ralleo et al relates to a salvage device for sunken ships, planes or the like and it particularly relates to a salvage device of the inflatable type. The salvage device is a pontoon device comprising inner and outer inflatable bags, said inner bag being partitioned into a series of compartments. The pontoon device comprises a tube extending from the exterior of the pontoon, through the outer bag and the inner bag to permit passage of pressure gas into the bag so as to inflate the pontoon. A plurality of hooks are provided on a fabric strap which securely encircles the pontoon. The pontoon is attached to the side of the ship by means of fastening these hooks to eyelets provided on the side of the vessel.
The rest of the patents are merely representative of what is in the prior art.